Don't let anyone destroy your Christmas Joy.
There are people who want to do this. Why? Because of the end times move to try and destroy all that is good and especially all that is Christian.
If they say: People shouldn't be giving gifts...
The wise men gave gifts, and they were accepted. Jesus was the ultimate gift to us from God Almighty, and we accepted. We give gifts to each other because giving to make others happy and comforted is a serious part of Chrisitanity. There is nothing wrong with continuing the tradition and giving good gifts!
If they say: You don't know if he was really born on the 25th..
So what? There is enough evidence that indicates it's the correct date. It's also the traditional day that our ancestors celebrated. December 25th IS THE DAY we celebrate Jesus' birthday, so questioning like this is only to disrupt the joy of a birthday for God.
If they say: There is something wrong with Christmas Trees:
Don't let it bother you. Read all about the serious connections to Christianity through the Christian Christmas Tree decoration.
If they say, Christmas is commercialized by the secular world..
Focus on the good point: Christmas is one of the ONLY times of the year when even godless people take some time to think about Jesus Christ!
Don't let anyone (even other supposed "christians") try to destroy your Christmas joy! Enjoy it! Praise God! Praise Jesus for the best time of the year!